Film-forming Amines Research Articles

Analysis of a film-forming amine response in impedance spectra

In this study, a detailed analysis of the dielectric response of a film-forming amine (1,3 N-oleyl propanediamine (OLDA)) in impedance spectra is presented, addressing both “bulk” OLDA and adsorbed OLDA layer on a carbon steel surface. The dielectric response of the “bulk” OLDA in the absence of electrolyte over an extensive temperature range (-150 °C to 50 °C) was explored by broadband dielectric spectroscopy (BDS). Subsequently, the response of the OLDA adsorbed layer on the steel surface was analysed by electrochemical impedance spectroscopy (EIS), for various immersion times (2 min to100 min) and temperatures (25 °C to 75 °C) in an aqueous NaCl solution.Impedance spectra (BDS and EIS), interpreted through the complex conductivity formalism, showed a resistive behaviour in the mid-frequency range and a capacitive behaviour at higher frequencies. The high frequency capacitive response in EIS spectra was shown to contain contributions from the OLDA layer and from the electrochemical double layer, as well. The temperature dependency of the OLDA conductivity was found to be similar to the temperature dependency of the electrolyte resistance, suggesting that the electrolyte (water and ions) crossed the OLDA layer to reach the steel surface. The presence of gauche defects in the OLDA alkyl chain, revealed by polarization modulation infrared reflection absorption spectroscopy (PM-IRRAS) analyses, may be a contributing factor to the disorder in the adsorbed layer, facilitating electrolyte infiltration.

Adsorption kinetics and inhibition mechanisms of a film-forming amine on carbon steel surfaces

In the present study, the inhibition mechanisms and the adsorption kinetics of a film-forming amine (N-oleyl-1,3-propanediamine, OLDA) were investigated on a carbon steel surface in various corrosive environments, relevant to industrial water/steam circuits. In situ electrochemical characterizations including Electrochemical Impedance Spectroscopy (EIS) and polarization curves were combined with ex situ surface analysis, such as Polarization Modulation Infrared Reflection Absorption Spectroscopy (PM-IRRAS) and Raman Spectroscopy. OLDA acts as a mixed inhibitor for all the studied conditions. In a deaerated medium, OLDA adsorption is temperature-independent (25 °C–50 °C) and PM-IRRAS analyses reveal the formation of a monolayer (thickness of about 1.6 nm) on the steel surface. In aerated media, mixed OLDA/corrosion products layers are formed exceeding the monolayer thickness (about 20 nm). Finally, the presence of a well-defined time constant in the high frequency range in impedance spectra is correlated with the accumulation of OLDA molecules with corrosion products.

Study on the Effect of Polyamine Water Treatment Agent on Metal Corrosion Inhibition in Boiler Steam-Water System.

A polyamine water treatment agent was prepared with the film-forming amine (N-oleyl-1,3-propylenediamine) and the neutralizing amine (cyclohexanamine) under optimal conditions. The copper sulfate liquid drop experiment showed that a protective film was formed by the polyamine water treatment agent on carbon steel. The analyses of the polarization curve and electrochemical impedance spectroscopy of carbon steel indicated that the polyamine water treatment agent exhibited geometric effects, which could inhibit both anode and cathode reactions of carbon steel, and the corrosion inhibition effect of the polyamine water treatment agent showed an extreme-concentration phenomenon. A metal corrosion experiment in a simulated boiler steam-water system indicated that the polyamine water treatment agent mitigated the corrosion of carbon steel at different temperatures, and the corrosion inhibition rates of the polyamine water treatment agent in liquid and gas environments at 150 °C were 53.84% and 67.43%, respectively, better than that at 350 °C. SEM-EDS characterization indicated that the formation of the corrosion product, iron oxide, on the carbon steel was reduced with the addition of the polyamine water treatment agent in the simulated boiler steam-water system.

Film-forming amine product as an alternative to carbohydrazide oxygen scavenger in high pressure boilers

Hydrazine has been largely replaced by carbohydrazide (CHZ) as an oxygen scavenger due to safety and health concerns and CHZ is now used in Saline Water Conversion Corporation (SWCC) high pressure boilers. However, the operational problem of phosphate hide-out has become a continuous challenge for the plant operators. Advances in boiler water treatment have shown that effective corrosion control and prevention of scaling can be achieved by using a mixture of film-forming and alkalizing amines and polycarboxylates [Film Forming Amine Product (FFAP)]. With the use of FFAP, carbohydrazide/ammonia treatment of make-up water and phosphate treatment in the drum will not be required. A uniform FFAP formulation was used throughout the test.The evaluation study was carried out at a boiler of the Yanbu Phase 1 Desalination and Power Plant (Mitsubishi) generating 60 MWh, with make-up water of 15 t h−1 producing 330 t h−1 steam at a pressure of 67 barg and temperature of 480 °C.The trial provided evidence that FFAP was a good alternative to use of an oxygen scavenger. Changeover from CHZ to FFAP without phosphate addition in the drum was done initially by dosing FFAP from both hydrazine tank and phosphate tank so that pH was maintained to the required values in both feed water and drum water. With the optimal dose rate (0.6 ppm) maintaining FFAP in the range of 0.3–1.0 ppm in feed water, all the key parameters (pH, ammonia and specific conductivity) were within the specified boiler design limits. The average corrosion rates on the water side were low for both CHZ and FFAP treatment (0.009 ± 0.001 mm y−1), however FFAP treated coupons showed much lower corrosion rates compared to CHZ in the steam side (0.0006 ± 0.0003 mm y−1 cf. 0.0075 ± 0.0006 mm y−1).

Nuclear Magnetic Resonance Analysis of Hydrothermal Reactions of Ethyl- and Octylamine in Sub- and Supercritical Water

Hydrothermal reactions of aliphatic amines have recently gained importance in relation to the application of amines as film-forming corrosion inhibitors for steam-water cycles. The kinetics and mechanism of the hydrothermal reactions of ethylammomiun cation (EtAH+) and n-octylammonium cation (OctAH+) were studied for comparison with the corresponding neutral amines to elucidate their reaction products and pathways at sub- and supercritical temperatures of 300-400 °C as model reactions of aliphatic ammonium cations. We analyzed the reaction of 13C-15N-labeled EtAH+ using NMR spectroscopy and revealed that the initial hydrolysis to ethanol, known as the main path, is followed by the elimination reaction producing ethene and the disproportionation reaction giving diethylammonium cation. The OctAH+ yields octene and octanol, each of which isomerizes to thermodynamically more stable species as the major products. Comparisons were made between the reactions of the neutral amines and ammonium cations to highlight their different reactivity. The hydrolysis, alkene formation, and dehydration of alcohols to alkenes were all found to be accelerated at low pH. The formation of low-molecular-weight organic acids such as acetic acid and formic acid was not observed. These results indicate that the corrosion protection effect of film-forming amines will be maintained under practical conditions with pH values as high as around 9 to 10, and hence side reactions involving byproducts will be suppressed.

Film-forming amines adsorption and corrosion kinetics on carbon steel surface in neutral solution investigated by EIS and PM-IRRAS analysis

N-oleyl-1, 3-propanediamine (OLDA) is one of the most used film-forming amines (FFAs) for the corrosion protection of carbon steel circuits of a wide range of industrial plants. The present work focused on the study of OLDA adsorption kinetics onto the carbon steel surface by electrochemical impedance spectroscopy (EIS). The diagrams were obtained in a 200 mg.kg−1 NaCl with and without OLDA for immersion times ranging from 2 min to 140 min and for two temperatures (25°C and 50°C). It was shown that, from the beginning of immersion (2 min), OLDA adsorption and corrosion occurred simultaneously on the carbon steel surface. With increasing immersion time, a dynamic and competitive process between both phenomena was established until a steady-state was reached and the corrosion was slowed down. Ex situ Raman spectroscopy analyses revealed a heterogeneous distribution of the OLDA molecules on the surface with a preferential adsorption on the corrosion products, mainly γ-FeOOH. Ex situ Polarization Modulation Infrared Reflection Absorption Spectroscopy (PM-IRRAS) analyses confirmed the formation of mixed barrier layers (OLDA molecules/corrosion products) whose thickness increased with time and temperature.

FILM FORMING AMINE ADSORPTION MECHANISMS AND KINETICS ON DEAERATOR DRAIN PIPE OF PWR NUCLEAR POWER PLANT

FILM FORMING AMINE ADSORPTION MECHANISMS AND KINETICS ON DEAERATOR DRAIN PIPE OF PWR NUCLEAR POWER PLANT

Study of the influence of cooling water quality and inhibitors on the corrosion rate of brass in cooling water

At present, our country does not have an effective programme for the organization of water-chemical regimes of circulating refrigeration systems, solving three problems at the same time: the prevention of sedimentation, Reduction of corrosion rates of copper-based construction materials and avoidance of biological growth within the system and on heating surfaces. In addition, the influence of cooling water quality on the corrosion of copper-containing alloys in high-inertial water-cooling systems of turbine condensers has also been largely unknown. The use of film-forming amines (in particular, chelamine and octadesilamine) is a promising method to address this problem, but information on this issue is scarce. Therefore, it is essential to optimize the water-chemical modes of recycling cooling systems of turbine condensers in order to reduce the corrosion rate of brass. Thus, the aim of the work is to study the influence of the quality of cooling water and corrective reagents on the corrosion rate of brass in order to optimize the water-chemical modes of cooling systems of turbine condensers.

Applying Film-Forming Amines for Rendering Corrosion Resistance to Structural Materials of Equipment and Piping of Power Units at Nuclear Power Plants (NPP) (Review)

Applying Film-Forming Amines for Rendering Corrosion Resistance to Structural Materials of Equipment and Piping of Power Units at Nuclear Power Plants (NPP) (Review)

Effect of organic film on magnetite deposition behavior of alloy 690 steam generator tubes in simulated PWR secondary system

The purpose of this study is to elucidate the effect of a film forming amine (FFA) on the magnetite deposition behavior of Alloy 690 tube in the secondary coolant system of pressurized water reactors. By the addition of octadecylamine (ODA), which is a FFA, an organic film with a petal-like form was evenly formed on the surface of the steam generator (SG) tube. Regardless of the addition of ODA, all simulated deposits were verified as magnetite and had a polyhedral or spherical shape. The amount of deposits on the film-formed SG tube was reduced by approximately 58% compared to the deposits on the as-received SG tube. The influence of the film-formed surface of the SG tube is discussed from the point of view of wettability, zeta potentials, and resistance of the electric double layer.

Molecular Dynamics Simulation on the Corrosion Inhibition Mechanism of Octadecylamine Inhibitor Film

Octadecylamine (ODA), a well-known film-forming amine, recently finds increasing application in nuclear pressurized water reactors to protect carbon steel components in the secondary circuit against corrosion. To clarify the inhibition mechanism, molecular dynamics simulations were employed to study the diffusion characteristics of three commonly encountered species, H2O, O2, and Cl-, in the formed inhibitor film. The simulation results revealed that the formed film mitigates corrosion by effectively impeding the diffusion of corrosion species in the film. For various species, the film exhibits markedly different inhibition abilities.

Preparation of Film-Forming Amine Emulsion as Boiler Water Treatment Agent

In this study, the preparation method of the film-forming amine emulsion is explored by changing the sequence of different reagents, OLDA concentration, experimental temperature and OLDA/cyclohexylamine ratio. The stability of the film-forming amine emulsions prepared under different conditions is studied by observing if the emulsion delamination occurred after standing for several days. Results indicate that the sequence of different reagents, OLDA concentration, experimental temperature and OLDA/cyclohexylamine ratio affect the formation and stability of the film-forming amine emulsion obviously. The maximum content of OLDA in the film-forming amine emulsion could reach to 1.5 wt%, OLDA/cyclohexylamine ratio could be changed from 1:1 to 1:2.5, and room temperature could be as the experimental temperature. The stable film-forming amine emulsion could be prepared under the optimal conditions.

Adsorption behaviour of film-forming amine on pre-oxidized carbon steel surface

The maintenance of condenser main pipe is the key to achieve film-forming amine maintenance effectiveness. In this work, oxygen content, pH and temperature of the solution were controlled to simulate the condition of condenser main pipe, and magnetite coated carbon steel sample was prepared by pre-oxidization. CAM was used to characterize the hydrophobicity of film formed samples. Hydrophobic film was formed on pre-oxidized carbon steel samples when octadecylamine concentration reaches 20 mg/kg. SEM, EDS, EIS, and PD were used to characterize the influence of octadecylamine concentration on maintenance effectiveness. It was found that the maintenance effectiveness was enhanced and the corrosion rate was suppressed with the increase of octadecylamine concentration. FIB and TEM were used to detect the adsorbed octadecylamine film thickness founding that octadecylamine adsorbed onto the surface of pre-oxidized carbon steel by multi-layer adsorption mechanism.

Stress Corrosion Cracking Behavior of TP 439 and 690 TT under Film-Forming Amine Environment.

Film-forming amines have been widely used in thermal power plants for maintenance after shutdown, and there are more and more applications and researches in nuclear power secondary circuits for this purpose. However, in the direction of stress corrosion cracking, there is not much research on the influence of film-forming amines on metal materials. This article uses the high temperature slow strain rate test (SSRT) method to evaluate the influence of a commercial film-forming amine on the stress corrosion cracking behavior of two conventional island materials for PWR nuclear power plants. These two metal materials are the heat exchange tube materials of the high-pressure heater and steam generator in the high-temperature operation area of the secondary circuit of a nuclear power plant: TP 439 stainless steel and 690 TT alloy. The test analyzed the mechanical properties and fracture morphology. The test results show that in the test concentration range (<5 mg/kg), the film-forming amine will not affect the SCC of TP 439 stainless steel and 690 TT alloy under the condition of slow strain rate. The behavior has a significant impact. In practical applications, the general dosage of film-forming amine is 1-2 mg/kg. This data is lower than the film-forming amine concentration used in the experiment. Therefore, there is no need to worry about the obvious impact on the SCC behavior of TP 439 stainless steel and 690 TT alloy.

Inhibition of carbon steel corrosion in HCl solution using N-oleyl-1,3-propanediamine based formulation

The relatively environmentally benign ingredient diethyl-aminoethanol (DEAE) was introduced into the film forming amine (FFA) formulation based on the unsaturated diamine N-oleyl-1,3-propanediamine (NOPDA). The optimal FFA formulation was determined by orthogonal experiment. The high corrosion inhibition efficiency of 92.1% and the images of scanning electron microscopy (SEM) and atomic force microscopy (AFM) confirmed the excellent corrosion inhibition effect of the improved FFA formulation in 1.0 M HCl acidic environment. The results proved that DEAE could promote the emulsification and dissolution of NOPDA in aqueous solution and therefore facilitate its adsorption onto carbon steel surface. The weight loss experimental results showed that the adsorption of the FFA inhibitor onto metal surface was endothermic and conformed to Langmuir isotherm model. Electrochemical impedance spectroscopy (EIS) analysis proved that a protective film was formed on the surface of carbon steel to prevent the transfer of charge. Contact angle measurements indicated that the film formed on the surface of the carbon steel was hydrophobic. According to X-ray photoelectron spectroscopy (XPS) analyses and thermodynamic calculation, it is inferred that the adsorption mechanisms mainly involved chemisorption, electrostatic attraction and hydrogen bonding. The results of this study provide a good reference for the application of unsaturated fatty diamine. • Weight loss and EIS experiments were carried out to investigate the anti-corrosion performance. • The emulsification and dissolution of NOPDA in water could be promoted by DEAE. • NOPDA-based formulation exhibited excellent corrosion inhibition performance in HCl. • FFA adsorption isotherm and thermodynamics were studied. • SEM, AFM and XPS analyses were performed and anti-corrosion mechanisms were inferred.

Research Process on Water Treatment Agent of Boiler for Preventing Metal Corrosion in the Steam-water Cycle

The safe and economical operation of boiler is influenced significantly by the metal corrosion in the steam-water cycle. It is the most common way to add the water treatment agents into the boiler water to prevent metal corrosion. In this paper, the application situation and limitations of the traditional boiler water treatment agents were summarized. Then the research process of the film-forming amines was elaborated. First, the structure and composition of film-forming amines, their properties and the interaction mechanisms with metal materials were described. Second, the industrial application of the film-forming amines was considered. Third, the existing problems of film-forming amines were discussed. Finally the future development of the novel film-forming amines was prospected.

Liquid Chromatography–High-Resolution Mass Spectrometry-Based Target and Nontarget Screening Methods to Characterize Film-Forming Amine-Treated Steam-Water Systems

Film-forming amine products (FFAP) are frequently used as corrosion inhibitors in steam-water systems. To have a better understanding of their behavior in the treated system, a liquid chromatography coupled to the high-resolution mass spectrometry (LC–HRMS) method was developed. This method enabled the concurrent targeted quantitative analysis of the film-forming amine oleyl propylenediamine (OLDA) and the nontarget screening (NTS)-based analysis of potential degradation products of FFAP or other organic matter in the system. The method was applied to samples collected from an FFAP-treated industrial steam-water system. OLDA was detected at a concentration of 0.027 mg/L after the FFAP dosing in the low-pressure steam drum. A feature (a combination of mass-to-charge ratio and retention time associated with a signal intensity) prioritization workflow was designed and applied to the NTS results to focus on the potential thermal degradation products of FFAP that could affect the studied steam-water system. Six features were prioritized from a total of 4596 detected features. Structural elucidation of these features was attempted based on mass spectrometry fragmentation data. One of the prioritized features was successfully identified as 2,2′-(tridecylimino)diethanol, presumably a degradation product of the FFAP emulsifier. Because of the chemical structure of the molecule, 2,2′-(tridecylimino)diethanol was considered as noncorrosive to the system. Overall, the developed LC–HRMS method facilitated the efficient analysis of OLDA with a limit of quantification of 0.002 mg/L and a comprehensive monitoring of organic matter across the steam-water system, including potential degradation products of the dosed FFAP.

Effect of Film-Forming Amines on the Acidic Stress-Corrosion Cracking Resistance of Steam Turbine Steel

This work evaluates the effect of film-forming amines (FFA) on the acidic stress-corrosion cracking (SCC) resistance of NiCrMoV turbine steel. Contact angle measurements show an increased hydrophobicity of the surface when coating the steel with oleyl propylene diamine (OLDA). According to potentiodynamic measurements and post-mortem scanning electron microscopy (SEM) analysis, anodic dissolution and hydrogen embrittlement still occur when the steel is FFA coated. In situ constant extension rate testing (CERT) in acidic aqueous environment at elevated temperature of FFA-coated steel shows a ductility gain compared to non-coated steel, explained by a decrease in both corrosion rate and hydrogen uptake.

Linking Thermoelectric Effect and Adsorption of Film Forming Amine as a Corrosion Inhibitor for Industrial Systems

Film-forming amines, and, more specifically, Z-N-9-octadecenylpropane-1,3-diamine (OLDA), are efficient corrosion inhibitors that are widely used in industrial closed-loop water systems. The active...

Effect of octadecylamine concentration on adsorption on carbon steel surface

Octadecylamine is an effective film-forming amine that protects carbon steel from corrosion. In the present study, the effect of octadecylamine concentration on adsorption on a carbon steel surface was investigated in anaerobic alkaline solution by using SEM/EDS, TEM and the Materials Studio simulation techniques. TEM morphology observation and EDS elemental detection determine the thicknesses of octadecylamine film on a carbon steel surface, which are confirmed by the in-situ electrochemical impedance spectroscopy measurement and resistance calculation. The Materials Studio simulation reveals the number of octadecylamine film layers at different concentrations. Results obtained in this study indicate that adsorption of octadecylamine film on carbon steel proceeds with the multi-layer adsorption mechanism.